Year Number 1970 47600 1971 53500 1972 58100 1973 65100 1974 66400 1975 32800 1976 28200 1977 29200 1978 30800 1979 31400 1980 33500 1981 34100 1982 35100 1983 35300 1984 33900 1985 31000 1986 31700 1987 34600 1988 39500 1989 40300 1990 45000 1991 47000 1992 59900 1993 63300 1994 65900 1995 71600 1996 80500 1997 94700 1998 97600 1999 117200 2000 112462 2001 96049 2002 112324 2003 117404 2004 127025 2005 148604 2006 119668 2007 138093 2008 159135 2009 123551 2010 111961.407853906 2011 129004 2012 131870 2013 158096 2014 157702 2015 160003 2016 154448 2017 170444 2018 182753 2019 186711 2020 73742.363 2021 97777